1. Field of the Invention
This invention relates to the disinfection of liquids, especially those containing microbes, and combines the use of chemical disinfectants with the application of high potential gradients to a liquid medium containing microbes.
2. Description of the Related Art
High potential gradients applied to a medium containing microbes can destroy or deactivate the microbes. This has been known for at least fifty years. Sale and Hamilton were the first to publish definitive experimental data on this effect and to demonstrate that the effect was evidently due to the potential gradient per se, and not the result of heating or the passage of electric current. See, for example, A. J. H. Sale and W. A. Hamilton, Effect of High Electric Fields on Microorganisms I. Killing of Bacteria and Yeasts, Biochimica & Biophysica Acta 148, 781 (1967); W. A.Hamilton and A. J. H. Sale, Effects of High Electric Fields on Microorganisms II. Mechanism of Action of the lethal Effect, Biochimica & Biophysica Acta 148, 789 (1967); A. J. H. Sale and W. A. Hamilton, Effect of High Electric Fields on Microorganisms III. Lysis of Erythrocytes and Protoplasts, Biochimica & Biophysica Acta 163, 37 (1968). Subsequent microbiological studies by Benz and Lauger (see, for example, Roland Benz and P. Lauger, Kinetic Analysis of Carrier-Mediated Ion Transport by the Charge-Pulse Techniaue, Journ. Membrane Biol. 27, 171 (1976)), Zimmermann et al. (see, for example, Ulrich Zimmermann, J. Vienken & Gunther Pilwat, Development of drug Carrier Systems: Electrical Field-Induced Effects in Cell Membranes, Bioelectrochem. & Bioenergetics 7, 553 (1980); Ulrich Zimmermann, Peter Scheurich, Gunther Pilwat & Roland Benz, Cells with Manipulated Functions: New Perspectives for Cell Biology, Medicine & Technology, Angewandte Chemie 93, 332 (1981)), and Benz et al. (see, for example, Roland Benz, F. Beckers & Ulrich Zimmermann, Reversible Electrical Breakdown of Lipid Bilayer Membranes: A Charge-Pulse Relaxation Study, Journ. Membrane Biol. 48, 181 (1979); Roland Benz & Ulrich Zimmermann, Pulse-Length Dependence of the Electrical Breakdown in Lipid Bilayer Membranes, Biochimica & Biophysica Acta 597, 637 (1980)), showed that high potential gradients induce porosity in the membrane of a biological cell. Below a certain value of applied potential gradient--this critical value being of the order of 10 kV/cm--the induced porosity is reversible: That is, when the gradient is removed, the membrane regenerates its properties and the cell is not permanently affected. Whereas, for values of gradient above the critical value, porosity rapidly increases with increase in the applied gradient, and there is an increasing probability that the cell will be destroyed.
Various systems for applying high potential gradients to a medium containing microbes are disclosed in U.S. Pat. No. 5,048,404 to Bushnell et al. and in U.S. Pat. No. 5,235,905 to Bushnell et al.